I’m watching this right now:

As a grammarian, it bothers me a LOT. After all, this is money that is both dirty and sexy, not sexy money that also happens to be dirty. That necessitates the comma.

As a person, and as someone who technically works in “marketing,” it actually doesn’t bother me as much. Incorrect as it is, it adds a certain boldness to it. BOOM BOOM BOOM. Dirty Sexy Money. The comma would have taken away some of the impact….

The layout makes it look as though “dirty money” is a substantive, and “sexy” is either a modifier or a comment. “Sexy, dirty money” and “Dirty, sexy money” would be correct in a line of type. But you still would not want to insert a comma into that layout: the typographical layout is its own punctuation.